This invention relates to a novel method for preparing filter-coated phosphor particles.
Filter-coated phosphor particles and their use in viewing screens for cathode-ray tubes have been described previously; for example, in U.S. Pat. Nos. 3,308,326 to S. H. Kaplan, 3,875,449 to W. H. Byler et al and 3,886,394 to S. A. Lipp. As disclosed in these patents, filter material may completely cover the phosphor surfaces, or may only partially cover the surfaces of the phosphor particles. In the methods described in these patents, the filter material is prepared separately and then particles thereof are deposited on the surfaces of the phosphor particles.